In recent years, with an increasing shortage of energy, the growth of environmental awareness, the rapid development of science and technology, the population explosion, and a growing demand for electricity, it has become an urgent issue to search for alternative energy and to effectively save energy. With the continuous progress in semiconductor manufacturing process, switching power supply has been widely used in all kinds of electronic products, and most electronic products are developed for miniaturization and high power density to meet market demand. For these purposes, the switching frequency of switching power supply should be increased so as to reduce the volume of magnetic components.
Since the switching frequency is increased, the switching loss during the switching of the power switch assembly between ON and OFF states is increased. When an LLC Series Resonant Converter (LLC-SRC) is operated in a low voltage-high current output mode, since the output current of the secondary side is semi-sinusoidal current, an excessive ripple current is generated at the output terminal as the output current rises.
Therefore, to overcome the above defects structure, it has become an important issue in the art to improve the converter structure.